Recent studies have identified a protein product, designated Ob, which when injected into a mouse causes that animal to lose weight. See, e.g., Barinaga (1995) Science 269:475-476; Zhang, et al. (1994) Nature 372:425-432; Pelleymounter, et al. (1995) Science 269:540-543; Halaas, et al. (1995) Science 269:543-546; and Campfield, et al. (1995) Science 269:546-548. Mice deficient in active Ob gene product are grossly obese, but injection of the Ob protein causes the mice to curb their eating and shed fat.
Physiologically, it appears that the Ob protein has two activities, it decreases appetite and increases energy use, leading to metabolic deficit and loss of weight.
In the United States, up to one third of all Americans are overweight. Obesity is the cause of a myriad of serious health problems, including, e.g., sleep apnea, adult-onset diabetes, and heart disease. See, e.g., The Merck Manual. The availability of agonists and antagonists will be used to modulate these processes. The present invention provides these, as well as other proteins, useful, e.g., in determining the structure and mechanisms of weight and appetite regulation.